The present invention relates to Optical Maskless Lithography (OML). In particular, it relates to providing OML with a recognizable relationship to mask and phase-shift mask techniques.
For general background regarding the types of phase-shift mask techniques analogous to the inventions disclosed herein, reference is suggested to the article by Wilhelm Maurer, entitled “Application of Advanced Phase-Shift Masks”, which was accessible at http://www.reed-electronics.com/semiconductor/index.asp?layout=articlePrint& articleID=CA319210, as of Mar. 12, 2004.
Moore's law promises exponential growth in computer power at diminishing prices. This dynamic growth of processing power might lead one to think that semiconductor device manufacturing would be an adventuresome business, like wild-catting for oil. Just the opposite is true. Because manufacturing batches are very valuable and manufacturing processes are sensitive to even small mistakes, semiconductor device manufacturing is a conservative business. Qualification cycles and standards for new equipment and modifications of old equipment are lengthy and demanding. Even a small change is vetted extensively, before being released to production.
Applications commonly assigned, many of which have overlapping inventorship, have described an SLM-based system well-adapted to make masks. Additional work has been done to adapt the SLM technology to direct writing of chips. However, the acceptance cycle is most challenging.
An opportunity arises to introduce an SLM-based system that emulates patterns produced with traditional reticles, including reticles with phase shift patterns and OPC features. Producing patterns directly from an SLM that have small and understandable differences from patterns produced by masks has the potential to enhance user confidence and speed acceptance of a new system. It also can provide a direct path from prototyping small batches with direct writing to tooling for large batches with traditional reticles. Better, more easily configured and controlled, more resilient and transparent components and systems may result.